The current used jack used in a small car is almost operated manually. The operation way is to shake a bow shape handle to lift or descend an arm of the jack. In operating process, it is often that the jack is tilt due to an improper force applied thereon. Thus, a large force is necessary. This is difficult for a women. Besides, the prior art jack has a large volume or a heavy weight for enhancing the stability thereof. This is a larger burden to a women.
Therefore, electromotive jacks are developed. However, some torsional force releasing means are necessary to be connected between the jack and the motor. Since the structure is complex, and the cost is high and heavy burdens can not be lifted, Therefore, this prior art electromotive jack does not be used widely. Moreover, a motor with larger power and a heavy weight is used, and therefore, it is hard for a women to transfer it.
Therefore, there is an eager demand for a novel directly driving electromotive jack device for releasing a torsional force so as to improve the aforesaid defects in the prior art.